Great information here!
A little late to "answer" but I agree with Tee about the Carex. One of my very favorites is Carex 'Evergold'
Sedge (Carex oshimensis 'Evergold')
Ssgardener Our locations are similar so this Carex should work for you. I've got it planted in several spots, especially nice because it looks as good in deep shade as it does with a little more sun. It's not very tall but I love the bright variegation and the evergreen foliage looks as good in December as it does in July! I think if you could find something taller for the center of your containers it would look wonderful around the edges of the containers.
Re: 'Stoplight' - The photos of these always look wonderful but I have yet to see one in the gardens that looks as nice as the photos. I agree with Bob, with our heat and humidity, you're safer selecting one of the H. villosa cultivars.
Re: how early to plant? As long as the ground isn't frozen, the earlier the better! Again, I agree with Bob.
As long as the plants have been hardened off the plants are going to be much happier in the ground and their roots are going to get an early start when the soil starts warming up. One of the reasons we always promote fall planting, even as late as November! If you can get them into the ground before it freezes, it gives the plant an early jump on spring!
